The present invention is directed to a drive system for an ultracentrifuge and, more particularly, discloses a direct drive system for a high speed ultracentrifuge with an easily removable drive spindle unit with high speed bearings.
Typical drive systems for high speed ultracentrifuges are gear drive systems. Consequently, when it is necessary to repair the drive system, the removal of the entire gear train and drive assembly is necessary. Also, in high speed ultracentrifugation the chamber in which the rotor operates must have a vacuum environment in order to reduce the wind friction which otherwise would occur with the high speed rotation of the rotor in an air environment. Vacuum seals are required within the drive system in order to maintain the vacuum of the rotor chamber. These vacuum seals are normally found on the rotor shaft and are susceptible to continual wear requiring periodic replacement. Also, whenever it is necessary to remove the drive system for repair, the vacuum seals on the shaft must be replaced. The typical electric motors used in the gear drive ultracentrifuge systems have motor brushes which are also a source of wear and must be replaced periodically, requiring service of the motor. Again, this requires a major effort in the removal of the drive system for this maintenance function.
Some systems utilize an oil turbine drive system which is a direct drive system, but also requires a significant amount of maintenance. The spindle is connected to a turbine which receives oil within a compartment to rotate the spindle.
Although induction motors have been used to directly drive centrifuge spindles for rotors, the configuration of these centrifuges does not permit efficient and convenient repair and replacement of the worn parts. The spindle is not easily removable and the bearings are not connected to the spindle so that a significant effort is required to replace them.
In nearly all drive systems for high speed ultracentrifuges it is necessary to periodically maintain the drive assemblies to replace various parts which are susceptible to wear due to the high speed rotation of the drive spindle. Consequently, it is a paramount desire of designers and manufacturers of high speed ultracentrifuges to provide a system which will be conducive to relatively low and/or simplified maintenance functions.